Zhang, RuiWang, WeiyiMaier, Thomas A.Wang, MengStone, Matthew B.Chi, SongxueWinn, BarryDai, Pengcheng2018-11-122018-11-122018Zhang, Rui, Wang, Weiyi, Maier, Thomas A., et al.. "Neutron spin resonance as a probe of Fermi surface nesting and superconducting gap symmetry in Ba0.67K0.33(Fe1−xCox)2As2." <i>Physical Review B,</i> 98, no. 6 (2018) American Physical Society: https://doi.org/10.1103/PhysRevB.98.060502.https://hdl.handle.net/1911/103317We use inelastic neutron scattering to study the energy and wave-vector dependence of the superconductivity-induced resonance in hole-doped Ba0.67K0.33(Fe1−xCox)2As2 (x=0 and 0.08 with Tc≈37 and 28 K, respectively). In previous work on electron-doped Ba(Fe0.963Ni0.037)2As2 (TN=26K and Tc=17 K), the resonance is found to peak sharply at the antiferromagnetic (AF) ordering wave vector QAF along the longitudinal direction, but disperses upwards away from QAF along the transverse direction [Kim et al., Phys. Rev. Lett. 110, 177002 (2013)]. For hole-doped x=0 and 0.08 without AF order, we find that the resonance displays a ringlike upward dispersion away from QAFalong both the longitudinal and transverse directions. By comparing these results with calculations using the random phase approximation, we conclude that the dispersive resonance is a direct signature of isotropic superconducting gaps arising from nested hole-electron Fermi surfaces.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlePhysRevB.98.060502https://doi.org/10.1103/PhysRevB.98.060502